Process for the polymerization of vinyl esters and their derivatives or homologues or mixtures of these substances



Patented Aug. 16, 1938 UNITED STATES PATENT OFFICE Hermann Plauson,Hamburg, Germany, asslgnor to Biihm & Haas Company, Philadelphia, Pa.

No Drawing. Original application January 30,

1931, Serial No. 512,494.

Patent No. 2,086,093.

Divided and this application January 4, 1935,

Serial No. 358.

6 Claims.

This invention relates to the polymerization of vinyl esters, and theirderivatives or homologues or mixtures of these substances. Thisapplication is a division of Serial No. 512,494, flied January 30, 1931.

The polymerization of vinyl esters by direct heating or in the presenceof catalysts requires great care; in particular it is very diflicult toobtain the same degree of polymerization in successive batches becausethe temperature cannot be regulated uniformly throughout the mass.

According to the present invention, a process is provided by means ofwhich an exact and easy control of polymerization of any desired degreeis made possible. The process consists first in emulsifying themonomeric vinyl esters or their derivatives or homologues or mixtures ofthese substances by means of suitable dispersing agents and dispersionaccelerators and then heating the emulsion to effect polymerization ofthe dispersed vinyl ester.

Various substances may be added to the vinyl esters during the course ofpolymerization, by means of which the polymerization of the vinyl estersis changed in different ways and special characteristics are imparted tothe final products.

The process is carried out in general by emulsifying the pure vinylester in water by means of an emulsifying agent such as naphthenesulfonic acids (produced in the reflning of mineral oils) or their soapsand then subjecting the emulsion to polymerizing influences. Only thosedispersing agents are chosen which have little or no chemical action onthe products of polymerization.

Various polymerization accelerators may be used including organicperoxides, aldehydes, air, oxygen, nitrogen oxides, and anhydrides oforganic acids. When gaseous accelerators are employed, the product isimproved with respect to both strength and elasticity.

When the desired degree of polymerization is attained, the emulsifyingagent and the added substances can be removed by leaching or distilling.

The following specific examples relating to the polymerization ofemulsified vinyl esters are given by way of further illustration of theinvention:

Example 1.--500 grams vinyl acetate is emulsifled in 300 to 500 grams ofwater to which has been added a sulphonated castor oil or its soap. Thisemulsion is placed in a vessel of 2 liters capacity with about 1% of anorganic or inorganic superoxide and heated.

In Germany February 1, 1930 The heat of polymerization evolved isabsorbed by the water, part of which is evaporated. By permitting thesteam to escape the temperature may be easily controlled and an increaseof the temperature to above 100 C. prevented. Any water and vinyl estervolatilized may be condensed in a reflux condenser and returned to theemulsion. The vessel in which the polymerization is carried out isequipped with a stirrer and the emulsion is kept constantly agitated.

It is thus possible to polymerize the vinyl ester to any desired degreein a simple manner. When the desired degree has been obtained, theheating is stopped. Air may be blown through the emulsion duringpolymerization. This exerts a favorable influence on the product andalso assists in accelerating the polymerization.

Furthermore, there may be used as emulsion accelerators naphthenesulphonic acids (obtained by the refining of mineral oils), or theirsoaps, which in themselves react only slightly or not at all on thepolymerization products. The polymerization and control of thepolymerization states is accomplished as in Example 1.

There may be used as polymerization accelerators, in addition tosuperoxides, gaseous or vaporous substances, for example, air, oxygen,acid anhydrides, nitrogen oxides, etc. By treatment of the vinylcompounds with gaseous polymerization accelerators, it is possible toimprove the elasticity of the polymerization products. Additions ofacetic acid, acetals, aldehydes, etc., are permissible as polymerizationimprovement factors.

After the desired degree of polymerization has been reached, theemulsion medium, as well as the other added substances, may be removedby washing or distillation.

Irradiation with ultra-violet light for the purpose of accelerating thepolymerization and improving the polymerizate can be used and isincluded in the scope of the invention.

What I claim is:--

1. The process of forming aqueous dispersions of vinyl esters whichcomprises emulsifying the monomeric ester in water containing anemulsii'ying agent which has no chemical action on the products ofpolymerization and subjecting the emulsion to polymerizing influences.

2. The process of forming aqueous dispersions of vinyl esters whichcomprises emulsifying the monomeric ester in water containing anemulsifying agent which is a member of the group consisting of naphthenesulfonic acids and their soaps and sulfonated castor oil and its soapsand subjecting the emulsion to polymerizing in-.

fluences.

3. The process of forming dispersions of polymerized vinyl acetate whichcomprises emulsifying the monomeric vinyl acetate in water by means ofan emulsifying agent that has no chemical action on the products ofpolymerization and subjecting the emulsion to polymerizing influences.

4. The process of forming dispersions of polymerized vinyl acetate whichcomprises emulsifying the monomeric vinyl acetate in water by means ofan emulsifying agent which is a member of the group consisting ofnaphthene sulfonic acids and their soaps and sulfonated castor oil andits soaps and subjecting the emulsion to polymerizing influences.

5. The process of forming dispersions of polymerized vinyl esters whichcomprises emulsifying the monomeric ester in water by means of anemulsifying agent that has no chemical action on the products ofpolymerization and heating the emulsion to the reaction temperature.

6. The process of forming dispersions of polymerized vinyl acetate whichcomprises emulsifying the monomeric vinyl acetate in water by means ofan emulsifying agent that has no chemical action on the products ofpolymerization and heating the emulsion to the reaction temperature.

HERMANN PLAUSON.

